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Annual and Interim Progress Report Summaries

Principal Investigator: Robert Gallo

Project: FLSC Phase I & II Clinical Trials

Submitted June 1, 2012

The overall aim of this program is to evaluate whether a full-length single chain gp120-CD4 complex (FLSC) has properties that will focus immune responses and better protect against HIV, when administered as a boost to vCP1521 in a Phase 2 study to be performed in Thailand (Objective 2). Objective 1 was planned to prepare and release FLSC clinical trial material, perform the supportive preclinical studies, and demonstrate safety and immunogenicity of the product when formulated in Alum in a Phase 1 clinical trial. In year 1 of objective 1, we have completed much of activity 1- process and cell line development. Our accomplishments include (1) identification of an upstream process that reproducibly yields 2-3 gms/liter of FLSC; (2) identification of a non-lectin based downstream process that gives 90% recovery; (3) FLSC purified using the process retains CD4i structure and immunogenicity; (4) Release assays identified and transferred to the CMO (Catalent Pharma Solutions); (5) Suitable formulation with Alum has been identified to yield 95% adsorption. (6) Master cell bank manufactured and undergoing preclinical testing. In addition, the manufacturing site for bulk drug substance production (Middleton, WI) and CRO that will execute preclinical toxicology testing (CRL, Montreal, CA) have been audited and qualified. Progress on Objective 2 awaits definition of ideal dose of FLSC in Objective 1.

Studies in objective 3, indicate that the A32-like domain (a key ADCC target) is atypically exposed on the 92TH023 envelope and on the corresponding vCP1521 vaccine construct. ALVAC constructs that expresses either soluble or membrance bound FLSC are being developed and subsequently characterized for its antigenic properties and capacity to protect non human primates (NHP) from virus challenge.

Objective 4 has been revised to a challenge study in NHP that tests the efficacy of FLSC with EM005 as adjuvant and an immunogenicity study in NHP that tests the immunogenic potentials of 4 different adjuvants. Both studies are expected to commence shortly.

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